Help needed with brake controller

[Dhardy193]

I just installed a tekonsha p3 in my 2020 30x. The controller lights up but does not detect trailer brakes when connected to a known working trailer. I detect that I have a signal on the brake output (blue wire) from the controller but can’t detect it on the pin in the trailer connection. Am I missing something I used a tekonsha 3034-p harness btw.

[jyh818]

Are your other lights in the 7 pin socket on the back working?

[Dhardy193]

Yes all lights are working

[LCBOYER]

Check your trailer ground